A rock which mysteriously appeared in images taken two weeks apart by Nasa’s
Mars rover leaves scientists baffled

Scientists are trying to work out how a rock mysteriously appeared in images taken two weeks apart by Nasa’s Mars rover, Opportunity.

The rover, which landed in an area known as Meridiani Planum a decade ago, is exploring the rim of a crater for signs of past water.

Another rover, Curiosity, touched down on the opposite side of the planet in 2012 for a more ambitious mission to look for past habitable environments.

At the moment, however, there is another question. On Jan 8, Opportunity sent back a picture of its work area, showing a white rock, about the size of a doughnut, where only bedrock could be seen before.

Scientists suspect the rock, nicknamed “Pinnacle Island”, was flipped over by one of the rover’s wheels, or deposited after a meteorite landed nearby.

"Much of the rock is bright-toned, nearly white," NASA said in a statement on Tuesday. "A portion is deep red in color. Pinnacle Island may have been flipped upside-down when a wheel dislodged it, providing an unusual circumstance for examining the underside of a Martian rock."